Lipid profiles for intrahepatic cholangiocarcinoma identified using matrix-assisted laser desorption/ionization mass spectrometry

Abstract

Background: We evaluated whether direct tissue matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) analysis of lipids may distinguish intrahepatic cholangiocarcinomas from adjacent normal tissue and from other adenocarcinomas that frequently metastasize to liver. Methods: Four pairs of frozen surgical specimens of cholangiocarcinomas and adjacent normal tissue were analyzed using histology-directed, MALDI MS analysis. 2,5-dihydroxybenzoic acid / alpha-cyano-4-hydroxycinnamic acid were manually deposited on tumor-rich areas, and mass spectra were acquired using a MALDI-time of flight instrument. Results: Cholangiocarcinomas and adjacent normal tissue samples demonstrated different lipid profiles, as evidenced by permutation P value < 0.05 for the cross-validated misclassification rate. Cancer-associated lipid alteration was similar between cholangiocarcinomas and pancreatic cancers, but not between cholangiocarcinomas and colorectal cancers. Baseline lipid profiles were different between cholangiocarcinoma and colorectal cancers. Conclusions: MALDI MS analysis of lipid distinguishes cancerous epithelium of cholangiocarcinoma from adjacent normal tissue, and between cholangiocarcinomas and colorectal cancers.